RATIONALE: Drugs used in chemotherapy, such as melphalan and dexamethasone, work in different ways to stop the growth of plasma cells, either by killing the cells or by stopping them from dividing. Having an autologous stem cell transplant to replace the blood-forming cells destroyed by chemotherapy, allows higher doses of chemotherapy to be given so that more plasma cells are killed. By reducing the number of plasma cells, the disease may progress more slowly. It is not yet known whether combination chemotherapy is more effective than chemotherapy followed by an autologous stem cell transplant in treating primary systemic amyloidosis.

PURPOSE: This randomized phase III trial is studying the side effects and how well giving low-dose melphalan together with dexamethasone works compared with high-dose melphalan followed by an autologous stem cell transplant in treating patients with primary systemic amyloidosis.

Organ response was evaluated on the basis of improvement of one or more affected organ; only one parameter was required to satisfy the criteria. Response needed to be maintained for a minimum of 3 months to be considered valid.

Renal response required a 50% reduction in 24-hour urine protein excretion (at least 0.5 g/d) with stable creatinine. Cardiac response required one of >= 2-mm reduction in the interventricular septal (IVS) thickness by echocardiogram, or improvement of ejection fraction by >= 20%, or improvement by 2 NYHA classes without an increase in diuretic use. Hepatic response required either >= 50% decrease in (or normalization of) an initially elevated alkaline phosphatase level or reduction in the size of the liver by at least 2 cm by radiographic determination. Gastrointestinal tract improvement was defined as normalization of a low serum carotene level, or reduction of diarrhea to < 50% of previous movements/day, or decrease in fecal fat excretion by 50%.

Compare the overall and progression-free survival of patients treated with these regimens.

Compare the regression of organ involvement in patients treated with these regimens.

Compare the duration of response in patients treated with these regimens.

Correlate clonal burden and time to in vitro amyloid formation with clinical outcomes in patients treated with these regimens.

Compare quality of life of patients treated with these regimens.

Compare the information-seeking behavior in patients treated with these regimens.

OUTLINE: This is a comprehensive cohort study comprising a randomized option and a nonrandomized option. Patients consenting to randomization are stratified by risk group (high vs low) and ECOG performance status (0-1 vs 2). They are then randomized to 1 of 2 treatment arms. Patients not consenting to randomization choose their treatment arm.

Arm I: Patients receive low-dose melphalan IV over 15-30 minutes on day 1 or orally once daily on days 1-7 and oral dexamethasone on days 1-4 and 22-25. Treatment repeats every 6 weeks for 10 courses in the absence of disease progression or unacceptable toxicity.

Blood and bone marrow samples are collected at baseline. Samples are examined by PCR, cDNA, and nucleotide sequence analysis to determine VH and VL gene families and carrier status. Urine is collected at baseline and analyzed for light-chain protein levels by exclusion chromatography.

Quality of life is assessed at baseline, at months 3, 9, and 12, at completion of study treatment, and then every 6 months for up to 5 years.

After completion of study treatment, patients are followed every 6 months for up to 10 years.

Eligibility

Ages Eligible for Study:

18 Years and older (Adult, Senior)

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

DISEASE CHARACTERISTICS:

Histologically confirmed primary systemic amyloidosis

Amyloid light-chain (AL) disease

Monoclonal protein by immunoelectrophoresis or immunofixation of the serum or urine OR abnormal free light-chain ratio

Diffuse interstitial pulmonary AL disease allowed if pulmonary function is adequate to allow safe transplantation NOTE: *Presence of amyloid deposits in a plasmacytoma or in bone marrow vessels in an asymptomatic patient does not constitute an amyloid syndrome

No secondary or familial amyloidosis

No multiple myeloma with lytic or destructive bone lesions or myeloma cast nephropathy

No multiple myeloma with > 30% plasma cells in the bone marrow

No amyloidosis manifested only by carpal tunnel syndrome or purpura

PATIENT CHARACTERISTICS:

ECOG performance status 0-2

Platelet count ≥ 100,000/mm³

Bilirubin ≤ 2.0 times upper limit of normal (ULN)

Alkaline phosphatase ≤ 6 times ULN

Creatinine ≤ 3.0 mg/dL

No NYHA class IV heart disease

Not pregnant or nursing

Negative pregnancy test

Fertile patients must use effective contraception

No uncontrolled infection

No HIV positivity

PRIOR CONCURRENT THERAPY:

Prior alkylating agents, immunosuppressive drugs, or steroids allowed provided they were given for < 1 month

Therapeutic steroid doses of ≤ 15 mg per day (or equivalent) allowed at discretion of physician

No concurrent participation in another clinical trial involving a pharmacologic agent

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00477971